Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure
page tables are properly synchronized when calling p*d_populate_kernel().
It is inteneded to synchronize page tables via pgd_pouplate_kernel() when
5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging
is used.
This fixes intermittent boot failures on systems using 4-level paging
and a large amount of persistent memory:
BUG: unable to handle page fault for address: ffffe70000000034
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] SMP NOPTI
RIP: 0010:__init_single_page+0x9/0x6d
Call Trace:
<TASK>
__init_zone_device_page+0x17/0x5d
memmap_init_zone_device+0x154/0x1bb
pagemap_range+0x2e0/0x40f
memremap_pages+0x10b/0x2f0
devm_memremap_pages+0x1e/0x60
dev_dax_probe+0xce/0x2ec [device_dax]
dax_bus_probe+0x6d/0xc9
[... snip ...]
</TASK>
It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap
before sync_global_pgds() [1]:
BUG: unable to handle page fault for address: ffffeb3ff1200000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI
Tainted: [W]=WARN
RIP: 0010:vmemmap_set_pmd+0xff/0x230
<TASK>
vmemmap_populate_hugepages+0x176/0x180
vmemmap_populate+0x34/0x80
__populate_section_memmap+0x41/0x90
sparse_add_section+0x121/0x3e0
__add_pages+0xba/0x150
add_pages+0x1d/0x70
memremap_pages+0x3dc/0x810
devm_memremap_pages+0x1c/0x60
xe_devm_add+0x8b/0x100 [xe]
xe_tile_init_noalloc+0x6a/0x70 [xe]
xe_device_probe+0x48c/0x740 [xe]
[... snip ...]
Cc: <stable@vger.kernel.org>
Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [1]
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
---
arch/x86/include/asm/pgtable_64_types.h | 3 +++
arch/x86/mm/init_64.c | 5 +++++
2 files changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 4604f924d8b8..7eb61ef6a185 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void)
#define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
#endif /* USE_EARLY_PGTABLE_L5 */
+#define ARCH_PAGE_TABLE_SYNC_MASK \
+ (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
+
extern unsigned int pgdir_shift;
extern unsigned int ptrs_per_p4d;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 76e33bd7c556..a78b498c0dc3 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
sync_global_pgds_l4(start, end);
}
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+{
+ sync_global_pgds(start, end);
+}
+
/*
* NOTE: This function is marked __ref because it calls __init function
* (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
--
2.43.0On Mon, Aug 11, 2025 at 02:34:20PM +0900, Harry Yoo wrote:
> Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure
> page tables are properly synchronized when calling p*d_populate_kernel().
> It is inteneded to synchronize page tables via pgd_pouplate_kernel() when
> 5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging
> is used.
>
I think it's worth mentioning here that pgd_populate() is a no-op in 4-level
systems, so the sychronisation must occur at the P4D level, just to make this
clear.
> This fixes intermittent boot failures on systems using 4-level paging
> and a large amount of persistent memory:
>
> BUG: unable to handle page fault for address: ffffe70000000034
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 0 P4D 0
> Oops: 0002 [#1] SMP NOPTI
> RIP: 0010:__init_single_page+0x9/0x6d
> Call Trace:
> <TASK>
> __init_zone_device_page+0x17/0x5d
> memmap_init_zone_device+0x154/0x1bb
> pagemap_range+0x2e0/0x40f
> memremap_pages+0x10b/0x2f0
> devm_memremap_pages+0x1e/0x60
> dev_dax_probe+0xce/0x2ec [device_dax]
> dax_bus_probe+0x6d/0xc9
> [... snip ...]
> </TASK>
>
> It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap
> before sync_global_pgds() [1]:
>
> BUG: unable to handle page fault for address: ffffeb3ff1200000
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 0 P4D 0
> Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI
> Tainted: [W]=WARN
> RIP: 0010:vmemmap_set_pmd+0xff/0x230
> <TASK>
> vmemmap_populate_hugepages+0x176/0x180
> vmemmap_populate+0x34/0x80
> __populate_section_memmap+0x41/0x90
> sparse_add_section+0x121/0x3e0
> __add_pages+0xba/0x150
> add_pages+0x1d/0x70
> memremap_pages+0x3dc/0x810
> devm_memremap_pages+0x1c/0x60
> xe_devm_add+0x8b/0x100 [xe]
> xe_tile_init_noalloc+0x6a/0x70 [xe]
> xe_device_probe+0x48c/0x740 [xe]
> [... snip ...]
>
> Cc: <stable@vger.kernel.org>
> Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [1]
> Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Other than nitty comments, this looks good to me, so:
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
> arch/x86/include/asm/pgtable_64_types.h | 3 +++
> arch/x86/mm/init_64.c | 5 +++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> index 4604f924d8b8..7eb61ef6a185 100644
> --- a/arch/x86/include/asm/pgtable_64_types.h
> +++ b/arch/x86/include/asm/pgtable_64_types.h
> @@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void)
> #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
> #endif /* USE_EARLY_PGTABLE_L5 */
>
> +#define ARCH_PAGE_TABLE_SYNC_MASK \
> + (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
> +
> extern unsigned int pgdir_shift;
> extern unsigned int ptrs_per_p4d;
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 76e33bd7c556..a78b498c0dc3 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
> sync_global_pgds_l4(start, end);
> }
>
Worth a comment to say 'if 4-level, then we synchronise at P4D level by
convention, however the same sync_global_pgds() applies'?
> +void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
> +{
> + sync_global_pgds(start, end);
> +}
> +
> /*
> * NOTE: This function is marked __ref because it calls __init function
> * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
> --
> 2.43.0
>
On Mon, Aug 11, 2025 at 12:46:32PM +0100, Lorenzo Stoakes wrote:
> On Mon, Aug 11, 2025 at 02:34:20PM +0900, Harry Yoo wrote:
> > Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure
> > page tables are properly synchronized when calling p*d_populate_kernel().
> > It is inteneded to synchronize page tables via pgd_pouplate_kernel() when
> > 5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging
> > is used.
> >
>
> I think it's worth mentioning here that pgd_populate() is a no-op in 4-level
> systems, so the sychronisation must occur at the P4D level, just to make this
> clear.
Yeah, that's indeed confusing and agree that it's worth mentioning.
Will do. The new one:
Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
ensure page tables are properly synchronized when calling
p*d_populate_kernel().
For 5-level paging, synchronization is performed via pgd_populate_kernel().
In 4-level paging, pgd_populate() is a no-op, so synchronization is instead
performed at the P4D level via p4d_populate_kernel().
> > This fixes intermittent boot failures on systems using 4-level paging
> > and a large amount of persistent memory:
> >
> > BUG: unable to handle page fault for address: ffffe70000000034
> > #PF: supervisor write access in kernel mode
> > #PF: error_code(0x0002) - not-present page
> > PGD 0 P4D 0
> > Oops: 0002 [#1] SMP NOPTI
> > RIP: 0010:__init_single_page+0x9/0x6d
> > Call Trace:
> > <TASK>
> > __init_zone_device_page+0x17/0x5d
> > memmap_init_zone_device+0x154/0x1bb
> > pagemap_range+0x2e0/0x40f
> > memremap_pages+0x10b/0x2f0
> > devm_memremap_pages+0x1e/0x60
> > dev_dax_probe+0xce/0x2ec [device_dax]
> > dax_bus_probe+0x6d/0xc9
> > [... snip ...]
> > </TASK>
> >
> > It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap
> > before sync_global_pgds() [1]:
> >
> > BUG: unable to handle page fault for address: ffffeb3ff1200000
> > #PF: supervisor write access in kernel mode
> > #PF: error_code(0x0002) - not-present page
> > PGD 0 P4D 0
> > Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI
> > Tainted: [W]=WARN
> > RIP: 0010:vmemmap_set_pmd+0xff/0x230
> > <TASK>
> > vmemmap_populate_hugepages+0x176/0x180
> > vmemmap_populate+0x34/0x80
> > __populate_section_memmap+0x41/0x90
> > sparse_add_section+0x121/0x3e0
> > __add_pages+0xba/0x150
> > add_pages+0x1d/0x70
> > memremap_pages+0x3dc/0x810
> > devm_memremap_pages+0x1c/0x60
> > xe_devm_add+0x8b/0x100 [xe]
> > xe_tile_init_noalloc+0x6a/0x70 [xe]
> > xe_device_probe+0x48c/0x740 [xe]
> > [... snip ...]
> >
> > Cc: <stable@vger.kernel.org>
> > Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> > Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [1]
> > Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
> > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
>
> Other than nitty comments, this looks good to me, so:
>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Thanks!
> > ---
> > arch/x86/include/asm/pgtable_64_types.h | 3 +++
> > arch/x86/mm/init_64.c | 5 +++++
> > 2 files changed, 8 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> > index 4604f924d8b8..7eb61ef6a185 100644
> > --- a/arch/x86/include/asm/pgtable_64_types.h
> > +++ b/arch/x86/include/asm/pgtable_64_types.h
> > @@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void)
> > #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
> > #endif /* USE_EARLY_PGTABLE_L5 */
> >
> > +#define ARCH_PAGE_TABLE_SYNC_MASK \
> > + (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
> > +
> > extern unsigned int pgdir_shift;
> > extern unsigned int ptrs_per_p4d;
> >
> > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> > index 76e33bd7c556..a78b498c0dc3 100644
> > --- a/arch/x86/mm/init_64.c
> > +++ b/arch/x86/mm/init_64.c
> > @@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
> > sync_global_pgds_l4(start, end);
> > }
> >
>
> Worth a comment to say 'if 4-level, then we synchronise at P4D level by
> convention, however the same sync_global_pgds() applies'?
Maybe:
/*
* Make kernel mappings visible in all page tables in the system.
* This is necessary except when the init task populates kernel mappings
* during the boot process. In that case, all processes originating from
* the init task copies the kernel mappings, so there is no issue.
* Otherwise, missing synchronization could lead to kernel crashes due
* to missing page table entries for certain kernel mappings.
*
* Synchronization is performed at the top level, which is the PGD in
* 5-level paging systems. But in 4-level paging systems, however,
* pgd_populate() is a no-op, so synchronization is done at P4D level instead.
* sync_global_pgds() handles this difference between paging levels.
*/
--
Cheers,
Harry / Hyeonggon
> > +void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
> > +{
> > + sync_global_pgds(start, end);
> > +}
> > +
> > /*
> > * NOTE: This function is marked __ref because it calls __init function
> > * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
> > --
> > 2.43.0
> >
On Tue, Aug 12, 2025 at 05:59:02PM +0900, Harry Yoo wrote:
> On Mon, Aug 11, 2025 at 12:46:32PM +0100, Lorenzo Stoakes wrote:
> > On Mon, Aug 11, 2025 at 02:34:20PM +0900, Harry Yoo wrote:
> > > Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure
> > > page tables are properly synchronized when calling p*d_populate_kernel().
> > > It is inteneded to synchronize page tables via pgd_pouplate_kernel() when
> > > 5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging
> > > is used.
> > >
> >
> > I think it's worth mentioning here that pgd_populate() is a no-op in 4-level
> > systems, so the sychronisation must occur at the P4D level, just to make this
> > clear.
>
> Yeah, that's indeed confusing and agree that it's worth mentioning.
> Will do. The new one:
>
> Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> ensure page tables are properly synchronized when calling
> p*d_populate_kernel().
>
> For 5-level paging, synchronization is performed via pgd_populate_kernel().
> In 4-level paging, pgd_populate() is a no-op, so synchronization is instead
> performed at the P4D level via p4d_populate_kernel().
That's great thanks!
>
> > > This fixes intermittent boot failures on systems using 4-level paging
> > > and a large amount of persistent memory:
> > >
> > > BUG: unable to handle page fault for address: ffffe70000000034
> > > #PF: supervisor write access in kernel mode
> > > #PF: error_code(0x0002) - not-present page
> > > PGD 0 P4D 0
> > > Oops: 0002 [#1] SMP NOPTI
> > > RIP: 0010:__init_single_page+0x9/0x6d
> > > Call Trace:
> > > <TASK>
> > > __init_zone_device_page+0x17/0x5d
> > > memmap_init_zone_device+0x154/0x1bb
> > > pagemap_range+0x2e0/0x40f
> > > memremap_pages+0x10b/0x2f0
> > > devm_memremap_pages+0x1e/0x60
> > > dev_dax_probe+0xce/0x2ec [device_dax]
> > > dax_bus_probe+0x6d/0xc9
> > > [... snip ...]
> > > </TASK>
> > >
> > > It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap
> > > before sync_global_pgds() [1]:
> > >
> > > BUG: unable to handle page fault for address: ffffeb3ff1200000
> > > #PF: supervisor write access in kernel mode
> > > #PF: error_code(0x0002) - not-present page
> > > PGD 0 P4D 0
> > > Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI
> > > Tainted: [W]=WARN
> > > RIP: 0010:vmemmap_set_pmd+0xff/0x230
> > > <TASK>
> > > vmemmap_populate_hugepages+0x176/0x180
> > > vmemmap_populate+0x34/0x80
> > > __populate_section_memmap+0x41/0x90
> > > sparse_add_section+0x121/0x3e0
> > > __add_pages+0xba/0x150
> > > add_pages+0x1d/0x70
> > > memremap_pages+0x3dc/0x810
> > > devm_memremap_pages+0x1c/0x60
> > > xe_devm_add+0x8b/0x100 [xe]
> > > xe_tile_init_noalloc+0x6a/0x70 [xe]
> > > xe_device_probe+0x48c/0x740 [xe]
> > > [... snip ...]
> > >
> > > Cc: <stable@vger.kernel.org>
> > > Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> > > Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [1]
> > > Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
> > > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> >
> > Other than nitty comments, this looks good to me, so:
> >
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>
> Thanks!
>
> > > ---
> > > arch/x86/include/asm/pgtable_64_types.h | 3 +++
> > > arch/x86/mm/init_64.c | 5 +++++
> > > 2 files changed, 8 insertions(+)
> > >
> > > diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> > > index 4604f924d8b8..7eb61ef6a185 100644
> > > --- a/arch/x86/include/asm/pgtable_64_types.h
> > > +++ b/arch/x86/include/asm/pgtable_64_types.h
> > > @@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void)
> > > #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
> > > #endif /* USE_EARLY_PGTABLE_L5 */
> > >
> > > +#define ARCH_PAGE_TABLE_SYNC_MASK \
> > > + (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
> > > +
> > > extern unsigned int pgdir_shift;
> > > extern unsigned int ptrs_per_p4d;
> > >
> > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> > > index 76e33bd7c556..a78b498c0dc3 100644
> > > --- a/arch/x86/mm/init_64.c
> > > +++ b/arch/x86/mm/init_64.c
> > > @@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
> > > sync_global_pgds_l4(start, end);
> > > }
> > >
> >
> > Worth a comment to say 'if 4-level, then we synchronise at P4D level by
> > convention, however the same sync_global_pgds() applies'?
>
> Maybe:
>
> /*
> * Make kernel mappings visible in all page tables in the system.
> * This is necessary except when the init task populates kernel mappings
> * during the boot process. In that case, all processes originating from
> * the init task copies the kernel mappings, so there is no issue.
> * Otherwise, missing synchronization could lead to kernel crashes due
> * to missing page table entries for certain kernel mappings.
> *
> * Synchronization is performed at the top level, which is the PGD in
> * 5-level paging systems. But in 4-level paging systems, however,
> * pgd_populate() is a no-op, so synchronization is done at P4D level instead.
> * sync_global_pgds() handles this difference between paging levels.
> */
>
That's great also, thanks!
> --
> Cheers,
> Harry / Hyeonggon
>
> > > +void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
> > > +{
> > > + sync_global_pgds(start, end);
> > > +}
> > > +
> > > /*
> > > * NOTE: This function is marked __ref because it calls __init function
> > > * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
> > > --
> > > 2.43.0
> > >
>
On Mon, Aug 11, 2025 at 02:34:20PM +0900, Harry Yoo wrote:
> Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure
> page tables are properly synchronized when calling p*d_populate_kernel().
> It is inteneded to synchronize page tables via pgd_pouplate_kernel() when
> 5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging
> is used.
>
> This fixes intermittent boot failures on systems using 4-level paging
> and a large amount of persistent memory:
>
> BUG: unable to handle page fault for address: ffffe70000000034
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 0 P4D 0
> Oops: 0002 [#1] SMP NOPTI
> RIP: 0010:__init_single_page+0x9/0x6d
> Call Trace:
> <TASK>
> __init_zone_device_page+0x17/0x5d
> memmap_init_zone_device+0x154/0x1bb
> pagemap_range+0x2e0/0x40f
> memremap_pages+0x10b/0x2f0
> devm_memremap_pages+0x1e/0x60
> dev_dax_probe+0xce/0x2ec [device_dax]
> dax_bus_probe+0x6d/0xc9
> [... snip ...]
> </TASK>
>
> It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap
> before sync_global_pgds() [1]:
>
> BUG: unable to handle page fault for address: ffffeb3ff1200000
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 0 P4D 0
> Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI
> Tainted: [W]=WARN
> RIP: 0010:vmemmap_set_pmd+0xff/0x230
> <TASK>
> vmemmap_populate_hugepages+0x176/0x180
> vmemmap_populate+0x34/0x80
> __populate_section_memmap+0x41/0x90
> sparse_add_section+0x121/0x3e0
> __add_pages+0xba/0x150
> add_pages+0x1d/0x70
> memremap_pages+0x3dc/0x810
> devm_memremap_pages+0x1c/0x60
> xe_devm_add+0x8b/0x100 [xe]
> xe_tile_init_noalloc+0x6a/0x70 [xe]
> xe_device_probe+0x48c/0x740 [xe]
> [... snip ...]
>
> Cc: <stable@vger.kernel.org>
> Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [1]
> Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
> arch/x86/include/asm/pgtable_64_types.h | 3 +++
> arch/x86/mm/init_64.c | 5 +++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> index 4604f924d8b8..7eb61ef6a185 100644
> --- a/arch/x86/include/asm/pgtable_64_types.h
> +++ b/arch/x86/include/asm/pgtable_64_types.h
> @@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void)
> #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
> #endif /* USE_EARLY_PGTABLE_L5 */
>
> +#define ARCH_PAGE_TABLE_SYNC_MASK \
> + (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
> +
> extern unsigned int pgdir_shift;
> extern unsigned int ptrs_per_p4d;
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 76e33bd7c556..a78b498c0dc3 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
> sync_global_pgds_l4(start, end);
> }
>
> +void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
> +{
> + sync_global_pgds(start, end);
> +}
> +
> /*
> * NOTE: This function is marked __ref because it calls __init function
> * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
> --
> 2.43.0
>
--
Sincerely yours,
Mike.
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